I have a specific question on my signature. I read somewhere that DP has some algorithm to curb bad links and make it nofollow even for premium members. I do not know why the algorithm has made my signature nofollow. Thought my sig site is PR 6 and has every other possible quality, I am wondering why this has happened. Any justification / correction from admin or mod would be highly appreciated.
You want get any justification, the will simply say there is no guarantee that your sig links will be dofollow.
The main issue is that the more we go into exact detail on how the algorithm works or what it's keying on, the more people will go out of their way to get around it. Plus the algorithm changes quite often, so something that is flagged today, might not be flagged tomorrow (or vice versa). Like dcristo says, there is no guarantee that ANY will be dofollow. It's best to just assume no link will be dofollow, and then if one is, great... it's a bonus.
Shawn, I can best understand your situation. Talking about the algo in public will lead to reverse engineering it. But can you do me a favor? Can you PM me the issue that is specific to my site? Just in case if I can correct anything on my site, I would be glad to do it. After all, paying for premium membership and it's looks little odd for me after seeing poor quality and low PR links being do-followed and my site being no-followed. Thanks.